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The capacity of absorption, the composition and the ratio of exchangeable cations of light sierozems of Karshi steppe
DOI: http://dx.doi.org/10.20534/ESR-16-9.10-9-10
Diyorova Mukhabbat Hurramovna, Karshi State University, Lecturer, The Faculty of Natural scinces
E-mail: Diyorova@mail.ru
The capacity of absorption, the composition and the ratio of exchangeable cations of light sierozems of Karshi steppe
Abstract: The materials provided in the present work characterizes the main elements of fertility and humus content on which depends the composition. The ratio of absorbed bases irrigated light sierozems are characterized as well. Key words: fertility, cations, absorbed, amount, humus, nutrient element, gross, mobil.
Introduction. The study of composition and properties of absorbed bases of soil is one of the main tasks of the theoretical soil science, from the depth of its solution flowing out an understanding of the appropriateness of the geographic distribution and reclamation of alkaline soil and the other soils, the development of the processes of soil in general. The founder of the doctrine of the absorption capacity of soils Tyurin I. V. [1, 33-34] mentioned: "All the properties of the soil, which will ultimately determine the value of the produced crop, depend to some extent on the size, nature and composition of the soil absorption complex. In close depending on the soil, there is the structure of soil, physical properties of soil and water, air, microbiological, nutritional and sanitary regime of the soil"
The doctrine of an absorption of the composition and proportions of exchangeable cations stands on a solid foundation of scientific works of scientists, such as, V. A. Kovda [2, 380-385], D. S. Or-lov, L. K. Sadovnikova, N. I. Sukhanova [3, 115-151], W. R. Kelley [4, 86-91] and others. Among the scientific papers, covering the composition and the ratio of absorbed cations in soils of the Central Asia, the works of P. N. Besedina [5, 84-92] express the greatest interest. These above mentioned and other authors have noted a low cation exchange capacity in soils of Central Asia.
It should be noted that today, it is very difficult to find the work materials related to the present sphere, the works in which one could find materials that enable to trace in time space. There is a lack of information giving an idea about the composition and properties of absorbed bases in Karshi steppe sierozems.
As for an actuality of the topic, basically the capacity exchange of irrigated soils of the region and an impact of certain factors on the composition and properties of exchange bases light sierozems of Karshi steppe determined relevance of the topic.
Research methods. During the research period from 2008 to 2015 in the survey area of the zone of influence of Mubarak gas processing plant of Kashkadarya region of the Republic of Uzbekistan, by depending on the condition of light sierozems, in survey area were laid 18 full-profile soil profiles. The selection, preparation, agrochemical analysis of soil samples carried out in accordance with adopted methods [6, 5-148].
Results of the research. It is known that sierozem is leaching from the soil profile, soil-forming rocks of water-soluble salts, gypsum sometimes carbonates. The leaching energy is reducing from dark to light sierozem. The results of the analysis of aqueous extracts of a number of sections of the object of study indicate that, the light sierozems contain in the upper horizons and the overall profile insignificant amount of water-soluble salts, and they ar belong to the group of non-saline soils. Carbonate horizon soils irrigating the light sierozems practically does not differ from the soil-forming rocks.
The soil-forming rock contains carbonates within the 6-9%, in carbonate-illuvial horizons it contains 7-10%. In composition of the carbonates in the studied soils, the magnesium carbonate is significantly less in comparison with the calcium carbonate.
The cations exchange capacity (CEC) is considered as a common indicator of the soil cation exchange properties. In English-language literature, this indicator means CEC (the cations Exchange capacity), [7, 206-237].
By own contain, the sum of exchangeable cations, or the sum of exchangeable bases can be considered as the close notion to the CEC. The results of analysis of the composition and amount of absorbed bases irrigated light sierozems are indicated in the following table.
Table 1. - The composition of absorbed bases irrigated light sierozems (n-8)
Depth, cm Meq. 100 g. of soil As a percentage of the amount
Ca++ Mg++ K+ Na+ Amount Ca++ Mg++ K+ Na+
S. Maymanak, profile 3
0-30 6,51 2,11 0,81 0,51 9,94 65,5 21,2 8,1 5,1
31-50 6,33 2,01 0,76 0,41 9,51 66,6 21,1 8,0 4,3
51-70 6,41 1,70 0,83 0,43 9,32 68,7 18,1 8,8 4,6
Karshi, profile 4
0-30 7,03 2,01 0,71 0,43 10,18 69,1 19,7 7,0 4,2
31-50 6,73 1,90 0,66 0.33 9,62 69,9 19,7 6,9 3,4
51-70 6,50 1,85 0,77 0,41 9,43 68,9 19,6 8,1 4,3
It should be noted, that the whole exchange capacity value of the sierozems of Karshi steppe is close to the same soils in other regions of Uzbekistan.
The soil absorbing complex of sierozems ofKarshi steppe is full of mostly alkaline earth cations, from which flow out that sierozem formation is not accompanied by the accumulation and the formation of sig-
nificant amounts of calcium and magnesium carbonates. The relatively high content of carbonates in these soils is the result of physical and chemical processes occurring in the soil-forming rocks of loess type.
The irrigated light sierozems differ from other soils of this series by containing low humus and other organic substances, as well as the gross and mobile forms of nutrients plants (Table 2).
Section 2. Biology
Table 2. - Agrochemical properties of irrigated light sierozems (n-8)
Depth, cm. Humus,% Gross,% Mobile mg/kg
Nitrogen Phosphorus Potassium Phosphorus Potassium
S. Maymanak, profile 3
0-30 1,38 0,088 0,120 1,720 19,46 300
31-50 0,91 0,082 0,090 1,846 15,80 340
51-70 0,80 0,038 0,103 1,880 16,30 290
Karshi, profile 4
0-30 1,20 0,120 0,141 1,884 12,70 280
31-50 0,96 0,079 0,136 1,902 19,80 310
51-70 0,63 0,045 0,125 1,916 17,73 295
Furthermore, it should be noted, that sierozem forming does not accompanying by the accumulation of large amounts of humus, nitrogen, phosphorus, potassium, where a relatively high content of potassium is associated with its contents in soil-forming rocks [8, 170-176]. During the scientific research of the mineralogical composition of irrigated light sierozems, found the significant amount of colloidal minerals such as montmorillonite, illite, vermiculite, kaolinit and etc., it is quite possible, that potassium vigorously enters into the crystal lattice of these minerals.
The above mentioned materials relating to water-soluble salts, carbonates and humus content and also nutrients contribute to low absorption capacity of these soil cations.
Irrigated light sierozems are characterized by a low amount of absorbed cations, due to the lack of humus and minerals with high capacity exchange.
This situation can be observed according to Kovda [2, 384385], which leads to the absorption capacity of the various components: 3-9 humic acid, 2.6 soil humus, 1-1.7 montmorillonite, 0.3-0.5 illite, 0.1-0.2 meq/g kaolinite. Consequently, exceptionally high absorbency humus and humic acids, as well as the montmorillonite group minerals substantially determines the absorption capacity of the soil. The soils in which organic matter is small, by the way the light sierozems are also included to them, an absorption capacity is not high.
The irrigated light sierozems of Karshi steppe are characterized by low absorption capacity, which contain very little humus and soil colloids. These soils are formed in sierozem zone and have an absorption capacity of not higher 9,37-10,18 meq/100 g of soil (Table 1).
One should note the high saturation of the absorbing complex of the studied soil alkaline bases, where the amount of absorbed calcium and magnesium constitute the 86,7-89,6% of the amount
of absorbed bases, the remaining 10,4-13,3% are potassium and sodium. The amount of absorbed magnesium in soils varies in 28,121,2% of the amount, which is almost 3 times or more less than the absorption of calcium.
Obviously, from the alkali metals potassium prevails, which varies between 6,9-8,1% of the amount. The amount of absorbed sodium varies in the range of 3,4-5,1%, which leads to the conclusion, that the soil is not alkaline. In the soil horizons as it approaches the surface, one can observe slow increase content of absorbed calcium and magnesium. This pattern of absorbed calcium and magnesium in sierozem forming linked together with other biological factors offsets of these elements. As for the almost equal distribution of absorbed calcium and magnesium in irrigated light sierozems of the studied area, this process is associated with the fact that in the past, these soils were passed the process of salinity and desalting, in which cation exchange takes place on a different principle.
Thereby, the results mentioned above show that, during agriculture irrigating process, the cation exchange capacity and its quality is in dynamic equilibrium, the growth of the cation exchange capacity is observing with an increase in cultivated soils. The high carbonate content and saturation of the absorbing complex of alkaline earth elements irrigating the light sierozems, give slightly alkaline reaction, where the pH of the aqueous extract in the upper horizons of the arable and sub-arable varies in the range of 7.2-7.8.
The capacitance value of exchange and the number of exchangeable bases such little humus irrigated light sierozems are not only more, depending on the humus content and texture, but also on the mineralogical composition and the amount ofthe clay fraction. In using of these lands into agriculture the maximum attention should be directed to the development of chemical reclamation of soils in order to preserve and increase the absorption of calcium and the reduction of absorbed magnesium, sodium in the soil absorbing complex.
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